Hiperpolarize

Hiperpolarize is the act of making a cell’s membrane potential more negative than its resting potential. In neurons, hyperpolarization increases the distance from the threshold for action potential generation and thus decreases the probability of firing. It is typically achieved by opening potassium channels, allowing K+ to leave the cell, or by opening chloride channels, allowing Cl- to enter. Active transport by the Na+/K+ ATPase or other ion pumps can contribute to prolonged hyperpolarization.

Hyperpolarization is a principal feature of inhibitory synapses. Neurotransmitters such as GABA and glycine promote Cl- influx, producing inhibitory postsynaptic potentials (IPSPs). Glutamatergic signaling generally causes depolarization, but modulators can influence the balance between excitation and inhibition.

In research and medicine, hyperpolarization is used to control neuronal excitability. Optogenetic tools such as halorhodopsin and archaerhodopsin enable rapid, reversible hyperpolarization of targeted neurons by light. Pharmacological agents that open K+ or Cl- channels or activate GABA receptors can induce hyperpolarization to address conditions involving excessive neuronal activity, such as epilepsy or chronic pain.

In cardiac tissue, hyperpolarization can affect conduction and refractoriness, contributing to the regulation of heart rhythm. The concept is discussed across physiology and neurobiology to explain how inhibitory signaling shapes timing and synchronization in neural networks.

The term hiperpolarize is often used in its anglicized form in discussions of neuronal signaling and electrophysiology, and may appear as a transliteration in non-English texts.